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Title: Spatiotemporal interactions in the visual cortex following paired electrical stimulation of the retina
Authors: Cicione, Rosemary
Fallon, James
Rathbone, Graeme
Williams, Chris
Shivdasani, Mohit
Keywords: Electric Stimulation/methods
Electrodes
Implanted
Evoked Potentials
Visual/physiology
Models, Animal
Retina/ physiology/surgery
Sensory Thresholds/physiology
Visual Cortex/ physiology
Visual Perception/ physiology
Visual Prosthesis
Issue Date: Nov-2014
Publisher: The Association for Research in Vision and Ophthalmology Inc.
Citation: Cicione, R., Fallon, J. B., Rathbone, G. D., Williams, C. E., & Shivdasani, M. N. (2014). Spatiotemporal interactions in the visual cortex following paired electrical stimulation of the retina. Investigative Ophthalmology & Visual Science, 55(12), 7726-7738.
Abstract: PURPOSE: Retinal prostheses use spatiotemporal patterns of electrical stimulation across multiple electrodes to provide visual percepts to blind patients. It is generally assumed that percepts produced by individual electrodes are independent of one another, which may not be the case. In this study, we aimed to quantify interactions between pairs of electrical stimuli delivered to the retina. METHODS: Normally sighted cats were implanted with a suprachoroidal electrode array. The retina was stimulated with a paired-pulse paradigm that consisted of a conditioning stimulus followed by a test stimulus, while recording multiunit activity in the visual cortex. Conditioning current, and spatial and temporal separation between the conditioning and test stimuli were varied. Cortical interactions were quantified by changes in multiunit activity elicited by stimulation with the paired-pulse paradigm, compared to stimulation of the test stimulus alone (control). RESULTS: Interactions varied as a function of conditioning current and temporal separation between the two stimulating pulses. Cortical activity increased compared to the control condition at an interstimulus delay of 1.025 ms and was significantly suppressed for delays between 20 and 90 ms, returning to near control levels for longer delays. The level of interactions increased when the conditioning current was increased. Interactions were found to be similar for electrode separations up to 3 mm. CONCLUSIONS: Interactions between sequential stimulation of pairs of electrodes in a suprachoroidal retinal prosthesis occur for delays up to 100 ms and electrode separations of several millimeters. Knowledge of these spatiotemporal interactions is essential for developing effective patterns of stimulation for retinal prostheses.
URI: http://repository.bionicsinstitute.org:8080/handle/123456789/121
ISSN: 1552-5783 (Electronic) 0146-0404 (Linking)
Appears in Collections:Bionic Vision Research Publications

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